// Contains some simple hashes to test proper calculation

// Taken and modified from Linux kernel (lib/crc16.c, see https://github.com/torvalds/linux/blob/master/lib/crc16.c)
// Licensed under GPL 2.0

/** CRC table for the CRC-16. The poly is 0x8005 (x^16 + x^15 + x^2 + 1) */
__constant unsigned short crc16_table[256] = {0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, 0xC601,
    0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440, 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81,
    0x0E40, 0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841, 0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00,
    0xDBC1, 0xDA81, 0x1A40, 0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41, 0x1400, 0xD4C1, 0xD581,
    0x1540, 0xD701, 0x17C0, 0x1680, 0xD641, 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040, 0xF001,
    0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240, 0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480,
    0xF441, 0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41, 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900,
    0xF9C1, 0xF881, 0x3840, 0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41, 0xEE01, 0x2EC0, 0x2F80,
    0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40, 0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640, 0x2200,
    0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041, 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281,
    0x6240, 0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441, 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01,
    0x6FC0, 0x6E80, 0xAE41, 0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840, 0x7800, 0xB8C1, 0xB981,
    0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41, 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40, 0xB401,
    0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640, 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080,
    0xB041, 0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241, 0x9601, 0x56C0, 0x5780, 0x9741, 0x5500,
    0x95C1, 0x9481, 0x5440, 0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40, 0x5A00, 0x9AC1, 0x9B81,
    0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841, 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40, 0x4E00,
    0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41, 0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680,
    0x8641, 0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040};

static inline unsigned short crc16_byte(unsigned short crc, unsigned char data)
{
    return (crc >> 8) ^ crc16_table[(crc ^ data) & 0xff];
}

__kernel void crc16(__global unsigned short* out, __global unsigned char const* in, unsigned len)
{
    unsigned short crc = 0;
    while(len--)
        crc = crc16_byte(crc, *in++);
    *out = crc;
}

// Taken and modified from https://en.wikipedia.org/wiki/Pearson_hashing

__constant unsigned char T[256] = {
    // 0-255 shuffled in any (random) order suffices
    98, 6, 85, 150, 36, 23, 112, 164, 135, 207, 169, 5, 26, 64, 165, 219,         //  1
    61, 20, 68, 89, 130, 63, 52, 102, 24, 229, 132, 245, 80, 216, 195, 115,       //  2
    90, 168, 156, 203, 177, 120, 2, 190, 188, 7, 100, 185, 174, 243, 162, 10,     //  3
    237, 18, 253, 225, 8, 208, 172, 244, 255, 126, 101, 79, 145, 235, 228, 121,   //  4
    123, 251, 67, 250, 161, 0, 107, 97, 241, 111, 181, 82, 249, 33, 69, 55,       //  5
    59, 153, 29, 9, 213, 167, 84, 93, 30, 46, 94, 75, 151, 114, 73, 222,          //  6
    197, 96, 210, 45, 16, 227, 248, 202, 51, 152, 252, 125, 81, 206, 215, 186,    //  7
    39, 158, 178, 187, 131, 136, 1, 49, 50, 17, 141, 91, 47, 129, 60, 99,         //  8
    154, 35, 86, 171, 105, 34, 38, 200, 147, 58, 77, 118, 173, 246, 76, 254,      //  9
    133, 232, 196, 144, 198, 124, 53, 4, 108, 74, 223, 234, 134, 230, 157, 139,   // 10
    189, 205, 199, 128, 176, 19, 211, 236, 127, 192, 231, 70, 233, 88, 146, 44,   // 11
    183, 201, 22, 83, 13, 214, 116, 109, 159, 32, 95, 226, 140, 220, 57, 12,      // 12
    221, 31, 209, 182, 143, 92, 149, 184, 148, 62, 113, 65, 37, 27, 106, 166,     // 13
    3, 14, 204, 72, 21, 41, 56, 66, 28, 193, 40, 217, 25, 54, 179, 117,           // 14
    238, 87, 240, 155, 180, 170, 242, 212, 191, 163, 78, 218, 137, 194, 175, 110, // 15
    43, 119, 224, 71, 122, 142, 42, 160, 104, 48, 247, 103, 15, 11, 138, 239      // 16
};

__kernel void Pearson16(__global const unsigned char* in, unsigned len, __global unsigned char* hash)
{
    unsigned i;
    unsigned j;
    unsigned char h;

    for(j = 0; j < 8; ++j)
    {
        h = T[(in[0] + j) % 256];
        for(i = 1; i < len; ++i)
        {
            h = T[h ^ in[i]];
        }
        hash[j] = h;
    }
}
